Lossless image compression and decompression method for high definition image and electronic device using the same

Abstract

A lossless image compression method for a high definition image is provided. The image compression method generates a minimum value of values produced by subtracting a current virtual pixel value from an average of neighbor pixels designated by a plurality of directions, as the prediction value of a current pixel. Thus, the image compression more efficient than the current JPEG-LS can be achieved.

What is claimed is: 
     
       1. An image decompression method comprising:
 extracting residual information by decoding a bit stream of a compressed image; 
 generating a prediction value of pixels of the image; and 
 restoring an original image using the residual information and the prediction value, 
 wherein the prediction value of a current pixel is a minimum value among values produced by subtracting a virtual pixel value of the current pixel from average values of neighbor pixels of the current pixel designated by a plurality of directions, and 
 wherein the virtual pixel value of the current pixel is different from a pixel value of the current pixel. 
 
     
     
       2. The image decompression method of  claim 1 , wherein, in the generating the prediction value, only some of the directions are used based on the virtual pixel value of the current pixel and neighbor pixel values of the current pixel. 
     
     
       3. An image decompression method comprising:
 extracting residual information by decoding a bit stream of a compressed image; 
 generating a prediction value of pixels of the image; and 
 restoring the image using the residual information and the prediction value, 
 wherein the decoding comprising referring to a lookup table which is updated according to a frequency of a residual component. 
 
     
     
       4. The image decompression method of  claim 3 , wherein, when the frequency of the residual component is greater than a frequency of a previous residual component, the lookup table which is updated by exchanging assigned integers is referred to. 
     
     
       5. The image decompression method of  claim 1 , wherein the bit stream of the compressed image comprises bit streams containing data relating to segments in the image. 
     
     
       6. An image compression method comprising:
 determining prediction values for pixels of an input image; 
 generating residual information of the pixels of the input image, based on the prediction values; and 
 encoding the generated residual information, 
 wherein a prediction value of a current pixel, among the prediction values, is a minimum value among values produced by subtracting a virtual pixel value of the current pixel from average values of neighbor pixels of the current pixel designated by a plurality of directions, and 
 wherein the virtual pixel value of the current pixel is different from a pixel value of the current pixel. 
 
     
     
       7. The image compression method of  claim 6 , wherein, in the determining the prediction value, only some of the directions are used based on the virtual pixel value of the current pixel and neighbor pixel values of the current pixel. 
     
     
       8. An image compression method comprising:
 determining prediction values for pixels of an input image; 
 generating residual information of the pixels of the input image, based on the prediction values; and 
 encoding the generated residual information, 
 wherein the encoding updates an encoder map and a decoder map according to a frequency of a residual component. 
 
     
     
       9. The image compression method of  claim 8 , wherein, when the frequency of the residual component is greater than a frequency of a previous residual component, the encoding updates an encoder map and a decoder map by exchanging assigned integers. 
     
     
       10. The image compression method of  claim 6 , further comprising: segmenting an input image to a plurality of subframes,
 wherein the determining of the prediction values, the generating of the residual information, and the encoding are performed on a subframe basis. 
 
     
     
       11. The image decompression method of  claim 1 , wherein the virtual pixel value of the current pixel is obtained such that at least one of red (R) and blue (B) values of the current pixel is predicted using a prediction value of a green (G) value of the current pixel. 
     
     
       12. The image compression method of  claim 6 , wherein the virtual pixel value of the current pixel is obtained such that at least one of red (R) and blue (B) values of the current pixel is predicted using a prediction value of a green (G) value of the current pixel.